With the prior art printers such as electronic typewriters, a bold-faced character may be printed by operation of a bold command key provided on a keyboard so that a central processing unit (CPU) produces a bold-face printing mode, in which a selected one of character keys is then operated to print a corresponding character in a bold-faced type.
More particularly, as shown in FIG. 7, a type element 1 of the selected character is struck by a print hammer in a first print position Pa to set the first print on a print sheet 3 via a print ribbon 2. Then, the print head is moved laterally along the print line to a second print position Pb which is spaced a distance from the first print position Pa so that the type element 1 overlaps a part of the character printed, and in which the second print is set. Likewise, the print head is again moved to a third print position Pc in which the third print is made to print the same character in an overlapping manner. Thus, the character is printed in a bold-face type. With an electronic typewriter capable of bidirectional printing, such three steps may be proceeded in the order opposite to that described above.
In such bold-face character printing operation with the prior art typewriters, the type element 1 makes a dint 6 in the print sheet 3 at the first print position Pa. When the type element 1 strikes the print sheet 3 in the second and third print position Pb and Pc, its front right side of the type element 1 is first brought into contact with a non-printed area of the print sheet 3 while at this time the front left side is in no contact with the print sheet 3 due to the dint 6 which has been formed in the first printing. The type element 1 will therefore tend to tilt in an arrow-indicated direction. This tendency will become much significant, when a center of gravity of the type element 1 is preset to be biased to the left with respect to the print sheet 3 for better printing quality.
Consequently, the impact of the type element 1 against the print sheet 3 is weakened at its right side, resulting in non-uniform ink setting or smudging at the rIght side of the bold-faced character 5 thus printed, as shown in FIG. 9.